It's widely considered the most contiguous SciFi series out there. The director started with 5 years of scripts and changed very little during production, other than losing the main character between seasons 2 and 3, due to medical complications. I personally consider Bab 5 to be as good, if not better than both Firefly and Farscape.
Between one and two. Even crazier, though - he knew actors sometimes left shows so he wrote in a “trapdoor” and replacement character so that he could sub out someone with a new character without losing a step.
It's cheesy and cheap and often very manichaean. Yet, it's very interesting and got me hooked to an extent that nothing on the Star Trek universe managed to.